The present invention relates to the field of viewing devices which employ sinusoidal patterns of illumination for examining objects and producing high resolution images thereof, and is readily applicable to the field of microscopy.
In the literature, one finds the suggestion of illuminating an object with an interference fringe pattern formed by laser beams in order to measure the amplitude of a fourier component. However, there is no known teaching as to how one can apply this suggestion to the construction of a viewing device such as a microscope. More particularly, there is no teaching as to how one can measure the phase of the fourier components nor how the different fringe patterns required are to be created to produce a practical apparatus. While the production of interference patterns at the specimen viewed by a microscope is known in the art, there is no known prior art which teaches the method and apparatus of the present invention. For example, the interference pattern produced by the arrangement of U.S. Pat. No. 3,162,713 is employed to obtain visual contrast and does not otherwise teach the present invention. Other prior art U.S. Pat. Nos. 3,495,890; 3,511,554; 3,180,216; 3,558,210; and 3,182,551 all illustrate various microscopes which require precision optical components in contrast with the present invention, which has a principal object to eliminate expensive, precision optical components.
It is thus an object of the present invention to provide a new form of microscopy which is capable of producing high resolution with a large depth of field without precision optical components.
While the present invention in its preferred form is directed to the use thereof as a microscope, other applications may involve telescopes, video cameras or other viewing systems where one might wish to recover only a few fourier components to obtain partial or enhanced structural information, alignment information, or the like.